Sayyiduna Zayd bin Khalid al-Juhani (may Allah be pleased with him) narrates that the beloved Prophet (peace and blessings be upon him) led us in the morning prayer at al-Hudaybiyah, following the traces of rain clouds (in the mud) from the night. When he (peace and blessings be upon him) finished, he turned towards the people and said: "Do you know what your Lord has said?" They said: Allah and His Messenger know best. He (peace and blessings be upon him) said: "Some of My servants have entered the morning in a state of faith and some in a state of disbelief. Whoever said, 'We have been given rain by the grace and mercy of Allah', has believed in Me and disbelieved in the stars; and those who said, 'We have been given rain because of such-and-such', have disbelieved in Me and believed in the stars."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الاستسقاء / 6450